What it is and where it fits
The UXAB189750005: This handle shaft is the mechanical interface between the circuit-breaker operating mechanism and the panel door. When you're building out a VD4 switchgear lineup, this is the part that transmits the manual close/open action from the front handle through the door to the breaker truck. It's a machined metal shaft, N-1 variant, so verify the shaft length and keyway match your specific VD4 frame size before ordering — ABB runs several shaft configurations across the VD4 family.